Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a data acquisition method for an active power filter device in the development process. The method comprises hardware protection and software protection, collects the stored data in real time, and ensures the invention aims of storing the burst data appearing in the test and providing analysis processing under the condition of equipment safety, thereby accelerating the research and development speed and improving the product feasibility.
The technical scheme of the invention is as follows: a data acquisition method for an active power filter device in a development process comprises the processes of data acquisition, data analysis and data transmission display of the active power filter device; the data acquisition is divided into external data sampling and internal data detection, wherein the external data sampling comprises system voltage sampling and load current sampling; the internal data detection comprises direct current side voltage detection, output current detection, control panel temperature detection and IGBT temperature detection; the method is characterized in that: the collected high-voltage and large-current signals are converted into small-voltage signals through the sampling circuit and the operational amplifier conditioning circuit and are transmitted to the AD conversion chip; the data analysis process comprises the following steps: transmitting data acquired by the AD conversion chip to a DSP operation controller; the DSP operation controller separates a harmonic component and a reactive component in the load current through the instruction current operation circuit, calculates an instruction signal of the compensation current, transmits the instruction signal to the compensation current generation circuit, and outputs the required compensation current; the collected direct current side voltage and output current and load harmonic current generate PWM signals through coordinate transformation, PI control and space vector control, and amplitude protection is carried out on the direct current side voltage and the output current through the collected data size, wherein the PWM signals are command signals of compensation current; the data transmission display process comprises the following steps: firstly, alarm setting of abnormal conditions is carried out, the upper computer refreshes a data display window after receiving data output by the DSP operation controller, and the received data each time are stored.
The data acquisition method for the active power filter device in the development process is characterized in that: the alarm setting of the abnormal condition (for example, a three-wire four-wire system, a three-phase three-wire system is similar, and parameters can be changed at any time according to test requirements) is as follows: the system voltage threshold value is maximum 220V 1.15, and minimum 220V 0.85; the threshold value of the direct current side voltage is 800V 1.025 at the maximum value and 800V 0.975 at the minimum value; the threshold value of the output current is a maximum set current value 1.2 and a minimum set current value 0.8.
The data acquisition method for the active power filter device in the development process is characterized in that: the alarm of the abnormal condition is set as follows: when the temperature of the control board is higher than 46 ℃ and the temperature of the IGBT is higher than 105 ℃, abnormal temperature alarm operation is carried out, and an indicator light for displaying the abnormal interface temperature is turned on.
The data acquisition method for the active power filter device in the development process is characterized in that: collecting system voltage to perform phase-locked loop control and voltage distortion rate analysis; and collecting load current to perform coordinate transformation to obtain the harmonic current content and the current distortion rate.
The data acquisition method for the active power filter device in the development process is characterized in that: the collected voltage signal is subjected to voltage division through a three-phase voltage sampling circuit and is converted into a small voltage signal through an operational amplifier conditioning circuit, and the maximum value and the minimum value are controlled through a threshold comparison circuit; the load current is sampled by an external current transformer and then converted into a small voltage signal by an operational amplifier conditioning circuit; the direct current side voltage detection is realized in a direct detection mode, a detected high voltage signal is subjected to voltage division through a direct current side voltage sampling circuit, an operational amplifier conditioning circuit is converted into a small voltage signal, and maximum and minimum value control is performed through a threshold comparison circuit; the output current detection is sampled by an internal Hall current sensor and converted into a small voltage signal by an operational amplifier conditioning circuit, and the maximum value and the minimum value are controlled by a threshold comparison circuit; the temperature detection loop comprises control board temperature detection and IGBT temperature detection.
The data acquisition method for the active power filter device in the development process is characterized in that: the PWM control signal generation process comprises the following steps: 3/2 coordinate transformation is carried out on the voltage of the power grid and the load current respectively to obtain voltage e alpha, e beta and current i alpha, i beta under an alpha beta coordinate system; calculating active power p and reactive power q, and respectively passing through a low pass filter LPF to obtain direct current components p1 and q1 of power; calculating fundamental wave components iaf, ibf and icf of currents ia, ib and ic to be detected according to the obtained p1 and q 1; respectively subtracting respective fundamental wave components from three-phase currents of harmonic components iah, ibh and ich, and carrying out dq conversion on the harmonic components iah, ibh and ich obtained through calculation to obtain idh and iqh; carrying out dq conversion on the output current io to obtain ioq and iod, carrying out difference between a detected direct-current side voltage signal and an ideal voltage stable value, and obtaining a total voltage regulating quantity id through PI control; obtaining a Uq signal by the iqh and the ioq through a PI control circuit, obtaining a Ud signal by the d-axis signals idh and iod and id through the PI control circuit, and carrying out alpha-beta coordinate transformation on the Uq and the Ud to obtain Ualpha and Ubeta; and performing space vector operation to obtain the sector where the target vector is located and the action time, and finally obtaining the duty ratio parameter.
The invention has the beneficial effects that: firstly, can catch the analysis that unusual data provided active filter device signal and solve the support to very big acceleration research and development speed and product work efficiency. And secondly, the feasibility support of the active filter device product is improved, the equipment safety in the development process can be ensured, the inexplicable explosion phenomenon in the design and development process is avoided, and research and development personnel can not improve the design through data analysis. And thirdly, a protection threshold value can be input according to design tasks in research, development and product debugging, and development and design work of active power filter devices of different models is facilitated.
Detailed Description
The technical scheme of the invention is further explained by combining the attached drawings.
As shown in fig. 1 to 4, the data acquisition method for the active power filter device in the development process of the invention includes the processes of data acquisition, data analysis and data transmission and display of the active power filter device. For the active power filter device, system voltage needs to be acquired for phase-locked loop control and voltage distortion rate analysis; acquiring load current, and performing coordinate transformation to obtain harmonic current content and current distortion rate; and collecting direct-current side voltage and output current and load harmonic current to generate PWM signals through coordinate transformation, PI control and space vector control. The implementation mode is as follows: and 3/2 coordinate transformation is respectively carried out on the power grid voltage and the load current to obtain voltages e alpha and e beta and currents i alpha and i beta under an alpha beta coordinate system. The active power p and the reactive power q are calculated according to the definition, and then the power is respectively passed through a low pass filter LPF to obtain direct current components p1 and q1 of the power. The fundamental wave components iaf, ibf and icf of the currents ia, ib and ic to be detected can be calculated according to the obtained p1 and q 1. The harmonic components iah, ibh and ich can be obtained by respectively subtracting respective fundamental components from three-phase currents, and dq conversion is performed on the calculated harmonic components iah, ibh and ich to obtain idh, iqh. And meanwhile, carrying out dq conversion on the output current io (representing three phases) to obtain ioq and iod, carrying out difference between the detected direct-current side voltage signal and an ideal voltage stable value, and obtaining a total voltage regulating quantity id through PI control. And (3) obtaining Uq signals from the obtained q-axis signals iqh and ioq through a PI control circuit, obtaining Ud signals from d-axis signals idh, iod and id through the PI control circuit, and carrying out alpha-beta coordinate transformation on the Uq and the Ud to obtain Ualpha and Ubeta. And performing space vector operation to obtain the sector where the target vector is located and the action time, finally obtaining the duty ratio parameter, outputting a PWM control signal, namely an instruction signal of the compensation current, transmitting the instruction signal to a compensation current generation loop, and outputting the required compensation current. The amplitude protection of the direct current side voltage and the output current is realized through the acquired data size, the acquired signal obtains the maximum value and the minimum value in three phases through an amplifying circuit, and is compared with the maximum threshold value and the minimum threshold value set by hardware through a comparison circuit to obtain an alarm signal to control the running state, so that the hardware protection is realized. The invention also needs to collect temperature data to control the running environment condition when working.
As shown in fig. 2, in the present invention, data acquisition is divided into external data sampling and internal data detection, where the external data sampling includes system voltage sampling and load current sampling; the internal data detection comprises direct current side voltage detection, output current detection, control panel temperature detection and IGBT temperature detection. The system voltage is directly sampled, the collected large voltage signal is subjected to voltage division through a three-phase voltage sampling circuit, an operational amplifier conditioning circuit is converted into a small voltage signal, and a threshold comparison circuit is designed for maximum and minimum control; the load current is sampled by an external current transformer and then converted into a small voltage signal by an operational amplifier conditioning circuit; the direct current side voltage detection is realized in a direct detection mode, a detected high voltage signal is subjected to voltage division through a direct current side voltage sampling circuit, an operational amplifier conditioning circuit is converted into a small voltage signal, and a threshold comparison circuit is designed for maximum and minimum value control; the output current detection is converted into a small voltage signal through sampling of an internal Hall current sensor and conversion of the small voltage signal through an operational amplifier conditioning circuit, and a threshold comparison circuit is designed for maximum and minimum value control; the temperature detection loop comprises control panel temperature detection and IGBT temperature detection, and the output end of the temperature sampling loop directly generates a small voltage signal. The generated small voltage signals are all connected to the AD conversion chip.
As shown in fig. 3, the data analysis process in the present invention is: the AD conversion chip transmits data to the DSP operation controller through the SPI communication interface. The DSP operation controller separates harmonic components and reactive components in the load current through the instruction current operation circuit, calculates an instruction signal of the compensation current, transmits the instruction signal to the compensation current generation circuit, and outputs the required compensation current.
As shown in fig. 4, the data transmission display process of the present invention is: firstly, defining data transmission protocol content, designing the length of transmission content to be 95 bits according to data required to be included in each transmission, and respectively including 6 bits of working state, 6 bits of set working current value, 3 bits of starting operation, 9 bits of three-phase system voltage, 9 bits of three-phase load current, 9 bits of three-phase load harmonic current, 9 bits of three-phase output current, 3 bits of control board temperature, 6 bits of IGBT temperature, 18 bits of information code and 18 bits of direct-current side voltage. When the upper computer receives the data, whether the data length is equal to 95 is calculated, the key characters are matched, and if the data length is incorrect, data transmission abnormity is displayed immediately. The serial port output of the active power filter device outputs data according to the protocol. The data transfer protocol also needs to specify an instruction to start data transfer, and the length of the instruction is also set to 95, so that the contents of the instruction are consistent with those in the program diagram. The upper computer receives the instruction data and matches the length and the content in the program block diagram, the upper computer enters a data receiving state after the matching is successful, and the display interface starting indicator lamp is turned on to indicate that the current device enters an operating state and a data display window is to be refreshed. According to the data content defined by the data transmission protocol, the current working state and the set working current value of the active power filter device, the three-phase system voltage, the three-phase load current, the three-phase load harmonic current, the three-phase output current, the temperature information of the control board, the temperature information of the IGBT, the current working code display and the voltage information of the DC side can be obtained in each data transmission. And then designing a display interface, wherein the display interface comprises communication protocol setting, and serial port setting including VISA resource name, baud rate, data bit, check bit, stop bit and flow control needs to be set in a wired transmission mode. The wireless transmission mode needs to start TCP interception and set an IP address and a port number. The display interface design also comprises real-time display of received data, at least comprises display of the current working state and set current value of the active power filter device, display of three-phase system voltage, display of three-phase load current, display of three-phase load harmonic current, display of three-phase output current, display of temperature information of a control panel, display of temperature information of an IGBT, display of current working code and display of voltage information of a direct current side. The display interface design should also include startup operation status display, data abnormal status indication, output waveform display, storage location display of received data, current time display, and the like. The data abnormal state indication at least comprises state reading abnormal display, system voltage abnormal display, data transmission abnormal display, output current exceeding limit value display, temperature abnormal display, code abnormal display and direct current side voltage abnormal display. The output waveform at least comprises a three-phase output current waveform and a DC side total voltage change waveform. And finally, designing a block diagram interface, wherein the block diagram interface comprises a receiving transmission starting instruction matching logic design, a working state judgment design, a threshold judgment design and a data storage mode design. The alarm device also comprises an alarm design for abnormal conditions, and two modes of alarm prompt of an indicator lamp and alarm of a buzzer can be selected. The set threshold range is slightly stricter than the set value of hardware and program design, which is convenient for causing workers to carefully observe data and judge whether the data is abnormal or not. Setting the threshold value of the system voltage as 220V 1.15 at the maximum value and 220V 0.85 at the minimum value; the threshold value of the direct current side voltage is 800V 1.025 at the maximum value and 800V 0.975 at the minimum value; the threshold value of the output current is a maximum set current value 1.2 and a minimum set current value 0.8. And performing logic AND/OR judgment through the read actual data and the threshold value to monitor the abnormal condition. Aiming at temperature control, the temperature of a control board is set to be higher than 46 ℃, the temperature of an IGBT is set to be higher than 105 ℃, namely, temperature abnormity alarm operation is carried out, and an indicator light for displaying interface temperature abnormity is lightened, so that software protection is realized.
According to the invention, through the design of the display interface, the working state of the current device, the set working current value, the system voltage change condition, the load current and the load harmonic current, the output current value, the temperature information, the code information and the direct current side voltage can be observed. An indication of data anomalies can also be seen, as well as the output current waveform, the dc side voltage waveform. The data storage location can be found through the file path. Through the program block interface, the code for starting data transmission can be set, and the code length and the code content are matched with the device sending setting. And the working state code can be set, and the functions realized by the active power filter device can be divided into capacitive reactive output, inductive reactive output, harmonic filtering, three-phase unbalance compensation, harmonic source and the like. And a data threshold range and an alarm prompt can be set, wherein the data threshold range comprises a system voltage threshold range, an output current threshold range, an IGBT temperature threshold range and a direct-current side voltage threshold range, and the data threshold range and the alarm prompt are connected to Boolean indication through logical relation operation. The abnormal data can be observed through the display interface, and the abnormal data is accompanied with the alarm sound of the buzzer. The invention adopts the EXCEL storage mode, and can fully utilize the powerful data analysis function of the EXCEL to carry out data statistics and abnormal analysis.
The working process of the invention is as follows: and setting communication interface parameters on a display interface, wherein the communication interface parameters are consistent with the mode of the active power filter device which needs to be operated at present and selected for transmission. After the device is electrified, the information such as system voltage, load current and the like can be obtained, the working parameters of the test are set through the touch screen, and the start operation button is clicked. The upper computer receives a command for starting data transmission at first, and a startup and shutdown indicator lamp of a display interface is turned on to indicate that the device enters an operating state. And refreshing a data window at regular time next to the display interface, gradually displaying a complete waveform by the output waveform interface, and dynamically changing along with the refreshing time. While the data received each time is stored. The storage position is found, the EXCEL is opened, the change condition of data at each time can be observed, and therefore the abnormal data captured by the historical data by designers can be guaranteed no matter sudden shutdown caused by hardware protection or software protection, and the research and development speed is greatly promoted.